How do computers play chess?

“Ugh! I can’t believe I lost AGAIN!” Rita growled at her computer screen. Her younger sister, who had just walked into the room, looked curious. “What are you upset about? What did you lose?” she asked. Rita turned to her and whined, “I thought I would improve my chess skills by practicing against the computer, but I’ve already played three games and haven’t won ONCE!” Her sister giggled. “You never won a game against our cousin Raju either!” Rita glared at her. “I may be playing against a computer, but it plays just as well as Raju does!”